War of the Fourth Coalition

Napoleon reviews his troops shortly before the Battle of Jena-Auerstedt (14 October 1806), as painted by Horace Vernet

The Fourth Coalition was assembled in 1806, and Napoleon defeated Prussia at the Battle of Jena-Auerstedt in October. He marched against advancing Russian armies through Poland and was involved in the bloody stalemate of the Battle of Eylau on 6 February 1807.
After a decisive victory at Friedland, he signed the Treaties of Tilsit; one with Tsar Alexander I of Russia which divided the continent between the two powers; the other with Prussia which stripped that country of half its territory. Napoleon placed puppet rulers on the thrones of German states, including his brother Jérôme as king of the new Kingdom of Westphalia. In the French-controlled part of Poland, he established the Duchy of Warsaw with King Frederick Augustus I of Saxony as ruler.
With his Milan and Berlin Decrees, Napoleon attempted to enforce a Europe-wide commercial boycott of Britain called the Continental System. This act of economic warfare did not succeed, as it encouraged British merchants to smuggle into continental Europe, and Napoleon's exclusively land-based customs enforcers could not stop them.